User devices provide a function of displaying transmitted/received messages, and in recent years, smart phones provide a function of converting an individual message into data and storing and duplicating the data. Furthermore, a particular application distinguishes transmitted/received messages based on a date to inform users of message transmission/reception times and dates, and provides a function of displaying the transmission/reception times of the respective messages.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.